1 /**************************************************************************
2 *
3 * Copyright 2010, VMware, inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 #include "util/u_bitcast.h"
29 #include <math.h>
30
31 static bool
TAG(do_cliptest)32 TAG(do_cliptest)(struct pt_post_vs *pvs,
33 struct draw_vertex_info *info,
34 const struct draw_prim_info *prim_info)
35 {
36 struct vertex_header *out = info->verts;
37 /* const */ float (*plane)[4] = pvs->draw->plane;
38 const unsigned pos = draw_current_shader_position_output(pvs->draw);
39 const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
40 const unsigned ef = pvs->draw->vs.edgeflag_output;
41 unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
42 unsigned flags = (FLAGS);
43 unsigned need_pipeline = 0;
44 bool have_cd = false;
45 bool uses_vp_idx = draw_current_shader_uses_viewport_index(pvs->draw);
46 unsigned viewport_index_output =
47 draw_current_shader_viewport_index_output(pvs->draw);
48 int viewport_index = 0;
49 int num_written_clipdistance =
50 draw_current_shader_num_written_clipdistances(pvs->draw);
51
52 if (uses_vp_idx) {
53 viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
54 viewport_index = draw_clamp_viewport_idx(viewport_index);
55 }
56
57 unsigned cd[2];
58 cd[0] = draw_current_shader_ccdistance_output(pvs->draw, 0);
59 cd[1] = draw_current_shader_ccdistance_output(pvs->draw, 1);
60 if (cd[0] != pos || cd[1] != pos)
61 have_cd = true;
62
63 /* If clipdistance semantic has been written by the shader
64 * that means we're expected to do 'user plane clipping' */
65 if (num_written_clipdistance && !(flags & DO_CLIP_USER)) {
66 flags |= DO_CLIP_USER;
67 ucp_enable = (1 << num_written_clipdistance) - 1;
68 }
69
70 assert(pos != -1);
71 unsigned prim_idx = 0, prim_vert_idx = 0;
72 for (unsigned j = 0; j < info->count; j++) {
73 float *position = out->data[pos];
74 unsigned mask = 0x0;
75
76 if (uses_vp_idx) {
77 /* only change the viewport_index for the leading vertex */
78 if (prim_vert_idx == (prim_info->primitive_lengths[prim_idx])) {
79 prim_idx++;
80 prim_vert_idx = 0;
81 viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
82 viewport_index = draw_clamp_viewport_idx(viewport_index);
83 }
84 prim_vert_idx++;
85 }
86 float *scale = pvs->draw->viewports[viewport_index].scale;
87 float *trans = pvs->draw->viewports[viewport_index].translate;
88 initialize_vertex_header(out);
89
90 if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
91 DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
92 float *clipvertex = position;
93
94 if ((flags & DO_CLIP_USER) && cv != pos) {
95 assert(cv != -1);
96 clipvertex = out->data[cv];
97 }
98
99 for (unsigned i = 0; i < 4; i++) {
100 out->clip_pos[i] = position[i];
101 }
102
103 /* Be careful with NaNs. Comparisons must be true for them. */
104 /* Do the hardwired planes first:
105 */
106 if (flags & DO_CLIP_XY_GUARD_BAND) {
107 if (!(-0.50 * position[0] + position[3] >= 0)) mask |= (1<<0);
108 if (!( 0.50 * position[0] + position[3] >= 0)) mask |= (1<<1);
109 if (!(-0.50 * position[1] + position[3] >= 0)) mask |= (1<<2);
110 if (!( 0.50 * position[1] + position[3] >= 0)) mask |= (1<<3);
111 } else if (flags & DO_CLIP_XY) {
112 if (!(-position[0] + position[3] >= 0)) mask |= (1<<0);
113 if (!( position[0] + position[3] >= 0)) mask |= (1<<1);
114 if (!(-position[1] + position[3] >= 0)) mask |= (1<<2);
115 if (!( position[1] + position[3] >= 0)) mask |= (1<<3);
116 }
117
118 /* Clip Z planes according to full cube, half cube or none.
119 */
120 if (flags & DO_CLIP_FULL_Z) {
121 if (!( position[2] + position[3] >= 0)) mask |= (1<<4);
122 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
123 } else if (flags & DO_CLIP_HALF_Z) {
124 if (!( position[2] >= 0)) mask |= (1<<4);
125 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
126 }
127
128 if (flags & DO_CLIP_USER) {
129 unsigned ucp_mask = ucp_enable;
130
131 while (ucp_mask) {
132 unsigned plane_idx = ffs(ucp_mask)-1;
133 ucp_mask &= ~(1 << plane_idx);
134 plane_idx += 6;
135
136 /*
137 * for user clipping check if we have a clip distance output
138 * and the shader has written to it, otherwise use clipvertex
139 * to decide when the plane is clipping.
140 */
141 if (have_cd && num_written_clipdistance) {
142 float clipdist;
143 unsigned i = plane_idx - 6;
144 /* first four clip distance in first vector etc. */
145 if (i < 4)
146 clipdist = out->data[cd[0]][i];
147 else
148 clipdist = out->data[cd[1]][i-4];
149 if (clipdist < 0 || util_is_inf_or_nan(clipdist))
150 mask |= 1 << plane_idx;
151 } else {
152 if (!(dot4(clipvertex, plane[plane_idx]) >= 0))
153 mask |= 1 << plane_idx;
154 }
155 }
156 }
157
158 out->clipmask = mask;
159 need_pipeline |= out->clipmask;
160 }
161
162 /*
163 * Transform the vertex position from clip coords to window coords,
164 * if the vertex is unclipped.
165 */
166 if ((flags & DO_VIEWPORT) && mask == 0) {
167 /* divide by w */
168 float w = 1.0f / position[3];
169
170 /* Viewport mapping */
171 position[0] = position[0] * w * scale[0] + trans[0];
172 position[1] = position[1] * w * scale[1] + trans[1];
173 position[2] = position[2] * w * scale[2] + trans[2];
174 position[3] = w;
175 }
176 #if MESA_DEBUG
177 /* For debug builds, set the clipped vertex's window coordinate
178 * to NaN to help catch potential errors later.
179 */
180 else {
181 position[0] =
182 position[1] =
183 position[2] =
184 position[3] = NAN;
185 }
186 #endif
187
188 if ((flags & DO_EDGEFLAG) && ef) {
189 const float *edgeflag = out->data[ef];
190 out->edgeflag = !(edgeflag[0] != 1.0f);
191 need_pipeline |= !out->edgeflag;
192 }
193
194 out = (struct vertex_header *)((char *)out + info->stride);
195 }
196
197 return need_pipeline != 0;
198 }
199
200
201 #undef FLAGS
202 #undef TAG
203